crypto/openssh/kexgex.c

   1 /* $OpenBSD: kexgex.c,v 1.28 2014/01/09 23:20:00 djm Exp $ */
   2 /*
   3  * Copyright (c) 2000 Niels Provos.  All rights reserved.
   4  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "includes.h"
  28
  29 #include <sys/types.h>
  30
  31 #include <openssl/evp.h>
  32 #include <signal.h>
  33
  34 #include "buffer.h"
  35 #include "key.h"
  36 #include "cipher.h"
  37 #include "kex.h"
  38 #include "ssh2.h"
  39 #include "digest.h"
  40 #include "log.h"
  41
  42 void
  43 kexgex_hash(
  44     int hash_alg,
  45     char *client_version_string,
  46     char *server_version_string,
  47     char *ckexinit, int ckexinitlen,
  48     char *skexinit, int skexinitlen,
  49     u_char *serverhostkeyblob, int sbloblen,
  50     int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen,
  51     BIGNUM *client_dh_pub,
  52     BIGNUM *server_dh_pub,
  53     BIGNUM *shared_secret,
  54     u_char **hash, u_int *hashlen)
  55 {
  56         Buffer b;
  57         static u_char digest[SSH_DIGEST_MAX_LENGTH];
  58
  59         buffer_init(&b);
  60         buffer_put_cstring(&b, client_version_string);
  61         buffer_put_cstring(&b, server_version_string);
  62
  63         /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
  64         buffer_put_int(&b, ckexinitlen+1);
  65         buffer_put_char(&b, SSH2_MSG_KEXINIT);
  66         buffer_append(&b, ckexinit, ckexinitlen);
  67         buffer_put_int(&b, skexinitlen+1);
  68         buffer_put_char(&b, SSH2_MSG_KEXINIT);
  69         buffer_append(&b, skexinit, skexinitlen);
  70
  71         buffer_put_string(&b, serverhostkeyblob, sbloblen);
  72         if (min == -1 || max == -1)
  73                 buffer_put_int(&b, wantbits);
  74         else {
  75                 buffer_put_int(&b, min);
  76                 buffer_put_int(&b, wantbits);
  77                 buffer_put_int(&b, max);
  78         }
  79         buffer_put_bignum2(&b, prime);
  80         buffer_put_bignum2(&b, gen);
  81         buffer_put_bignum2(&b, client_dh_pub);
  82         buffer_put_bignum2(&b, server_dh_pub);
  83         buffer_put_bignum2(&b, shared_secret);
  84
  85 #ifdef DEBUG_KEXDH
  86         buffer_dump(&b);
  87 #endif
  88         if (ssh_digest_buffer(hash_alg, &b, digest, sizeof(digest)) != 0)
  89                 fatal("%s: ssh_digest_buffer failed", __func__);
  90
  91         buffer_free(&b);
  92
  93 #ifdef DEBUG_KEX
  94         dump_digest("hash", digest, ssh_digest_bytes(hash_alg));
  95 #endif
  96         *hash = digest;
  97         *hashlen = ssh_digest_bytes(hash_alg);
  98 }